Dump trucks or so-called large dump trucks are predominantly used in coal mining operations or ore mining operations for the transport of the mined coal, minerals and ores. These bulk material dumpers are manufactured in sizes of more than 90 metric tons (t) up to several 100 t in weight and payload so that they have very large dimensions overall.
A diesel electric drive is used as the traction drive, wherein the mechanical energy generated by a diesel engine is converted with the aid of an alternator into electrical energy for the supply of the electric traction drives. The reason for this process is that diesel engines, like all internal combustion engines, can only be operated with ideal efficiency in a very restricted speed range and cannot be started under load. The AC motors for the driving axle can also produce the desired torque in the lower speed range for starting. The internal combustion engine used can be operated continuously in the ideal speed range.
Corresponding power electronics are required for the control of the one or more electric motors and of the alternator. They as a rule include one or more frequency converters to regulate the required speed at the electric motors. The total power electronics were previously integrated into a common switch cabinet which was arranged on the upper deck of the dump truck in the region of the operator's cabin.
Due to the position and due to the huge dimensions of such dump trucks, an enormous effort has to be applied for the installation or dismantling of the switch cabinet since it can only be accessed with difficulty at a great height on the upper deck. Minor servicing work still has to be carried out by a correspondingly trained technician since there is a risk to life and limb for persons due to the high electrical powers. The switch cabinet can be opened for servicing work and the power electronics can be serviced or repaired on site.
However, it cannot always be ensured that a correspondingly trained technician is available at the deployment site for the repair and servicing of the power electronics. However, a complete replacement of the power electronics is not wanted or is not possible due to the described effort.
The present disclosure has for this reason set itself the object of finding a suitable solution for the design and the integration of the power electronics of a diesel electric drive of a work machine of the present category.
This object is achieved by a work machine, in particular in the form of a dump truck or of a truck, having a diesel electric drive, it is now proposed not to accommodate the power electronics in a common switch cabinet, but instead a modular concept is proposed according to which individual components of the power electronics are divided into individual modules by function, in particular into at least two or more modules, and at least one of the modules is accommodated on its own in an encapsulated housing. Ideally, all functional modules are accommodated in their own encapsulated housings. The individually encapsulated housings can be installed and disassembled individually. The work machine may include various of the features of work machines described herein, such as an upper deck, an operator cabin, etc., positioned as described above herein.
This approach offers the advantage that individual modules can be replaced more simply and in the event of a defect can be replaced in an uncomplicated manner with a new corresponding module on site at the deployment location. The power electronics, for example, no longer have to be repaired on site, but defective modules can be replaced. This is in particular sensible when no trained technician is available at the respective deployment site.
The replacement of individual functional modules is substantially simpler and more effective with respect to a conventional switch cabinet due to the smaller dimensions.
It is, for example, conceivable that the individual encapsulated housings do not provide any access in the form of a servicing flap, servicing door, etc. and are thus only suitable for on-site replacement, but not for on-site repair.
The encapsulated housing is produced from a solid material, metal, particularly from steel, stainless steel, aluminum or from a combination of the named material types. The integral power electronics can be protected from external influences such as moisture, stone chipping, dust, etc. by the solid material.
The division of the power electronics into individual functional modules can in particular take place such that individual electronic components are divided in dependence on the associated electrical consumers, i.e. on the electric motors. The required frequency converters for a first electric motor are, for example, integrated in a functional module, while the frequency converters for a second electric motor are integrated in a further functional module.
There is furthermore the possibility of providing at least one separate functional module for the required control electronics for controlling and/or regulating the alternator and/or the frequency converters of the further functional modules.
The encapsulated housings comprise one or more external electrical terminals for the cabling to the alternator, on the one hand, and for the cabling to one or more electric motors, on the other hand. The external terminals likewise serve the mutual coupling of the functional modules.
In addition to the electrical terminals, connections for an integrated cooling can be provided. External connections for the supply or removal of a corresponding cooling medium for the integrated cooling in at least one of the functional modules are conceivable. Each functional module ideally has its own integrated cooling with its own connections.
In a particularly preferred embodiment of the present disclosure, at least one receiving means is provided, in the form of a board or of another platform. The design in the form of a frame is also conceivable. The receiving means is suitable for a common receiving of two or more functional modules of the power electronics.
The housings of the individual functional modules are ideally configured in box shape so that they can be stacked on one another or can be arranged in rows next to one another in a space-saving manner. Two or more functional modules can be mounted above the receiving means at the work machine, in particular at the vehicle frame of the work machine. Additional protection from dust or stones swirled up from below results by using a platform as the receiving means for the individual functional modules. There is moreover the possibility of designing the receiving means as releasable to be able to disassemble the receiving means with the received functional modules together.
The functional modules can, for example, be assembled together in the region of the driven rear wheel axle of the work machine so that there are line paths which are as short as possible between the functional modules and the electric motors to be supplied. An arrangement of at least one power module or of all power modules between the alternator and the electric motors is particularly preferred. It is also conceivable to arrange some of the functional modules in the vehicle frame between the two longitudinal beams of the vehicle frame, while some others of the power modules are fastened to the outer side of the frame beams. There is moreover the possibility of assembling all functional modules at the outside to the frame rack, in particular at the left and/or right in the direction of travel.
In addition to the work machine in accordance with the present disclosure, the present disclosure relates to power electronics for the work machine in accordance with the present disclosure. The power electronics comprise two or more functional modules, with each functional module being accommodated in an encapsulated housing. The advantages and properties of the power electronics in accordance with the present disclosure obviously correspond to those of the work machine in accordance with the present disclosure so that a repeat description will be dispensed with at this point.
The present disclosure further relates to a diesel electric drive train having power electronics in accordance with the present disclosure. The same advantages and properties also apply with respect to the diesel electric drive train which have already been discussed and described in detail above. A repeat description is therefore dispensed with.
Further advantages and properties of the present disclosure will be explained in more detail in the following with reference to an embodiment shown in the Figures. There are shown: